Method and apparatus for gas lift producing of oil wells



July 12, 1966 D. CRYER 3,260,308

METHOD AND APPARATUS FOR GAS LIFT PRODUCING OF OIL WELLS Filed Dec. 4, 1964 5 Sheets-Sheet 1 INVENTOR.

Del Cryer A T TORNEYS July 12, 1966 D, CRYER 3,260,308

METHOD AND APPARATUS FOR GAS LIFT PRODUCING OF OIL WELLS Filed Dec. 4, 1964 5 Sheets-Sheet 2 July 12, 1966 D, CRYER 3,260,308

METHOD AND APPARATUS FOR GAS LIFT PRODUCING OF OIL WELLS Filed Dec. 4, 1964 5 Sheets-Sheet 5 17g. 9 /0 /3"L 2/4 4" a. 4 I Q ZZ/// 224 I I l 224 225 Q 4 7 x z? T" 7/7 United States Patent 3,260,308 METHOD AND APPARATUS FOR GAS LIFT PRODUCING OF OIL WELLS Del Cryer, 257 Pierremont Road, Shreveport, La. 71105 Filed Dec. 4, 1964, Ser. No. 416,030 13 Claims. (Cl. 166-8) This invention relates to a method and apparatus for automatic pneumatic lift and gas lift operation of oil wells and to an automatic pressure relief valve for use in such wells, and is a continuation-in-part of my application No. 46,63 8, filed August 4, 1960, now abandoned.

Gas lift operation of oil wells in the past has been wasteful of equipment and gas when operated individually, and unsatisfactory in performance and also wasteful of gas when operated in groups. Also, satisfactorily high production from individual oil wells has not been achieved, mainly because of small capacity reservoirs utilized with the gas lift operation and because of the back pressure remaining in the reservoir tubing after each lifting cycle initiated by pressurized gas.

Therefore, it is an object of my invention to provide a method for the automatic gas lift operation of oil wells which is both economical and successful in performance.

Another object of my invention is to provide apparatus for the gas lift operation of oil wells, either singly or in groups, which is economical to manufacture and gives improved performance.

Another object of my invention is to provide an automatic pressure relief valve which will permit the reservoir pressure to become equal to the pressure maintained on the oil well casing.

Another object of my invention is to provide means affording a larger reservoir for the accumulation of oil received from the well casing.

Another object of my invention is to provide an automatic pressure relief valve which is simple in construction, effective in operation and well designed to meet the demands of economic manufacture.

Other and further objects and advantages of my invention will be apparent from the following specification taken in conjunction with the accompanying drawings, wherein corresponding characters of reference designate the same or similar parts throughout the several views, and in which:

FIG. 1 is a diagrammatic layout view of the apparatus employed in my system.

FIG. 2 is a schematic wiring diagram of the apparatus shown in FIG. 1.

FIG. 3 is a side elevation of the automatic high pressure multiple outlet valve employed in my system.

FIG. 4 is a top plan view of the valve shown in FIG. 3.

FIG. 5 is a fragmentary vertical cross-sectional view of the valve shown in FIG. 3, with parts broken away.

FIG. '..6 is a fragmentary plan view of the valve shown in FIG. 3, with parts broken away.

FIG. 7 is a horizontal cross-sectional view taken along the line 7-7 in FIG. 5, on an enlarged scale.

FIG. 8 is a side view, partly in cross section, showing the valve of my device installed in an oil well casing.

FIG. 9 is a longitudinal cross-sectional view, on an enlarged scale, of a portion of the device shown in FIG. 8.

FIG. 10 is a fragmentary longitudinal cross-sectional view, on a still further enlarged scale, showing a portion of the device depicted in FIG. 9 with the upper valvein open position.

FIG. 11 is a transverse cross-sectional view along the line 11-11 in FIG. 10.

FIG. 12 is a transverse cross-sectional view along the line 1212 in FIG. 10.

FIG. 13 is a fragmentary longitudinal view showing a detail in partial cross section.

3,260,308 Patented July 12, 1966 FIG. 14 is a view similar to FIG. 13 with all parts in longitudinal cross section.

FIG. 15 is a transverse cross-sectional view along the line 15-15 in FIG. 13.

FIG. 16 is a transverse cross-sectional view along the line 1616 in FIG. 13

Referring more in detail to FIGS. l-7 of the drawings, the above ground system will be explained first. An important feature of this portion of my invention is the automatic high pressure multiple outlet valve 10, the details of which will be described hereinafter. Suffice it to say at this point that the valve is provided with a plurality of outlets to be connected respectively, to the several wells to be operated as a group, here shown as four in number and designated as 11, 11a, 11b and 11c. As is customary in the art, each of the wells is provided with a casing 12, a two-inch tubing 13 inside the casing, and a one inch tubing 14 inside the two-inch tubing. A n outlet of the valve 10 is connected to supply gas under pressure to the two inch tubing in each of the Wells by means of the pipe lines 15, 15a, 15b and 15c, respectively.

Another feature of my invention is that the one inch tubing at the top of each well is provided with an upward extension 16 beyond the coupling 17 at which the pipe 18 takes off the gas and oil coming up from the well through the one inch tubing 14. Similar extensions 16a, 16b, and 16c, couplings 17a, 17b and 170, and pipe lines 18a, 18b and are provided for the wells 11a,

11b and 11c, respectively. The extension 16, which is of course axially align with the one-inch tubing, is connected at its upper portion to one end of a small onequarter-inch tubing 19 which is connected at its other end to the pipe line 18. Similar connections are provided as shown at 19a, 19b and on the other wells.

The purpose of the extension 16 on the upper end of the one-inch tubing and the by-pass connection 19 is to provide a shock absorber for the rabbit customarily employed in gas lift operation of oil wells, and the functioning of this device will be explained hereinafter.

The pipe lines 18, 18a, and 18b and 180 may be connected directly to a gas and liquid separator, or they may be connected into a header 20 and thence through a common pipe line 21 to the gas and liquid separator 22 which will be recognized by those skilled in the art as a separator of prior art construction.

Liquid from the gas and liquid separator 22 is conducted by pipe line 23 to the oil and water separator 24, of conventional construction, from which waste water is taken by means of the conduit 25, and oil passes by means of the conduit 26 to the oil storage tank 27.

Gas from the gas and liquid separator 22 passes by means of pipe line 28 through the scrubber tank 29 and thence by pipe line 30 to the inlet side of the motor driven compressor 31 which supplies gas under pressure through the pipe line 32 in response to actuation of the pressure responsive switch 34 which is set to maintain pressure in the tank 33 between 500 p.s.i. maximum and 290 p.s.i. minimum, for example. Shut-off valve 35 is manually operated to be closed if it is desired to make repairs or changes in the valve 10. The multiple outlet valve 10 is automatically operated in response to electric timer 36 to supply operating gas under pressure through the pipe lines 15, 15a, 15b, and 150, selectively, to the wells being operated.

Another feature of my invention is that excess gas from the gas and liquid separator 22 which is not needed immediately for return to the gas storage tank 33, instead of being released as was previously done, is conducted by pipe line 38 into the casing of at least one of the wells for temporary storage under pressure, the pressure being controlled at about 15 p.s.i. by means of pressure relief valve 39 in the pipe line 38.

Referring more particularly to FIGS. 3 through 7 in the drawings, it will be seen that my automatic high presure multiple outlet valve comprises a cylindrical body 40 provided with a plurality of outlet ports 4-1, 41a, 41b and 410 communicating respectively with pipe lines 15, 15a, 15b and 150. The valve body 40 is closed at the bottom by bottom plate 42 and is closed at the top by top plate 43. The bottom plate 42 is supported upon a base plate 44 which is supported above floor plate 45 by a plurality of legs 46.

Interio-rly, the valve body 40 is provided with a rotor 47 which is journaled for rotation at 48 and 43 in the top and bottom plates, respectively. The rotor 47 has an outer periphery conforming closely to the inner periphery of the valve body 40 except in one small portion of its periphery, here shown as about 90 degrees, the rotor is cut away along a substantially straight line to form a cavity 50 between the rotor and the inner periphery of the valve body. Extending radially inward from the cut away portion of the periphery, the valve body is provided with a radial bore 51 which extends past the center of the rotor. Through the hub journaled at 49 in the bottom plate 42, the valve body is provided with an axial bore 52 which at its inner end is in communication with the radial bore 51 and at its outer end is in communication with pipe line 37 through swivel connections 37'. A Teflon plug or bushing 55 having an enlarged head 56, making it somewhat mushroom shaped, is provided with a through bore 57 axially thereof and is carried in the radial bore 51 in the rotor 47 with the outwardly extending flange of the underside of the enlarged head abutting the flattened cut away portion of the periphery of rotor 47. O ring 53 around the shank of the plug 55 prevents leakage from the radial bore 51 into the cavity 50 while permitting slight sliding movement of the plug 55 in the radial bore 51. The outer face of the Teflon plug or bushing 55 rests snugly against the inner periphery of the cylindrical valve body 40. In order to press the Teflon bushing 55 firmly against the inner wall of the valve body, the inner end of the Teflon bushing which is received within the bore 51 is abutted by a collar 58 which is pressed thereagainst by coil spring 59, the collar 58 being slidably positioned within the bore 51. The other end of the coil spring 59 is engaged over a floating plug 60 which is slidably mounted in a radial bore 51. The rotor is tapped and threaded to receive an adjusting screw 62 which loosely engages the floating plug 60 for in and out movement thereof to adjust the tension on spring 59 pressing the collar 58 and plug 55 outwardly against the inner periphery of the valve body 40. A screw driver or other tool may be inserted through one of the outlet ports in valve body for adjustment of the screw 62, this end of the radial bore 63 being closed by a pipe plug 64 after the adjustment has been made and until the next adjustment is necessary.

Extending upwardly from the rotor 47 through the journal at 48 is the rotor drive shaft 65 which is connected by gears 66, 67 through speed reducer 68 to the valve motor 69, the valve motor and speed reducer being mounted upon an upper plate 71 supported by a plurality of legs 71 mounted on the base plate 44. The gear 66 is provided on its upper face with an index plate 72 which carries a plurality of index lugs 73, one (for each outlet in the valve body, and one for each space between outlets, eight such lugs being here shown (FIG. 6) spaced 45 degrees apart corresponding to the spacing of the four outlets and four intermediate spaces in the embodiment of the valve as shown. The index lugs are arranged to engage the actuating finger 74 of the microswitoh 75.

In the operation of the foregoing system according to my invention, assuming that the rotor 47 in the multiple outlet valve is aligned with the Teflon bushing 55 overlying the outlet port 41, gas under pressure will pass from storage tank 33 through line 37 to the axial inlet bore 52 in the valve 10 and thence through the radial bone 5-1 and Teflon bushing 55 to the outlet port 41 with which the pipe line 15 is connected to supply the gas under pressure to the two-inch tubing in the well 11. The gas under pressure then passes down through the two inch tubing 13 opens the bottom hole gas lift valve (more fully disclosed hereinafter), and enters the lower end of one-inch tubing 14' to force the rabbit therein upwardly and carrying with it the accumulated fluid (gas and oil) which is taken off through the pipe line 18 at the coupling 17 until the rabbit passes the coupling 1'7. Thereafter, without the provision of my extension 16 on the one inch tubing, there would be a great hammering of the rabbit against the upper end of the tubing, but according to my invention the tubing 16 permits the rabbit to climb past the coupling 17 and the small amount of liquid remaining above the rabbit is forced out through the small onequanter-inoh diame-t er tubing 19 which forms a bypass back around the pipe line 18, this small by-pass tubing permitting the remaining liquid carried above the rabbit to escape slowly and thereby provide a cushioning effect for the rabbit which after coming to a stop, again descends to the bottom of the well through the one inch tubing to pick up another accumulation of fluid. This operation continues for the programmed time set on the timer 36 for lifting fluid from the well, and as gas continues to be supplied through the pipe line 15 the rabbit continues to operate up and down in the one inch tubing carrying above it each time a slug of fluid to be delivered through the pipe line 18 into the gas and liquid separator 22, the oil and water passing therefrom through the pipe line 23 into the oil and water separator 24 from whence the oil passes through the conduit 26 into the oil storage tank 27. Meanwhile, back at the gas and liquid separator 22, the gas passes out through the pipe line 28 through the scrubber 29 where any condensate is taken out and thence through the pipe line 30 to the inlet side of the motor driven compressor 31 which supplies compressed gas through the pipe line 32 to replenish the supply in the storage tank 33 so as to maintain the pressure therein approximately between 500 psi. maximum and 290 psi. minimum. Connected in parallel with the inlet side of the motor driven compressor 31 is the pipe line 38 which has its other end connected into the casing on well 11, for example, so that any gas coming through the pipe line 28 and not immediately needed or required by the inlet side of motor driven compressor 31 is temporarily stored in the casing 12 of well 11, thus providing a closed, recycling system for the utilization and storage of the gas coming from the oil field as an incident to the lifting of oil from the wells therein. Each of the other wells, in which gas. is not being stored, is provided with a gas let-off pipe line 181a, 181b, 1810, respectively, interconnecting the associated well casing with its associated pipe line to the gas and liquid separator 22, each such let-oil pipe line being provided with a check valve, as shown, to permit gas under pressure to flow from the well casing to the separator 22, but not reversely. It will be noted in FIG. 2 that the motor driven compressor 31 is connected across the electric supply line to supply gas under pressure to the storage tank 33 any time required in response to the actuation of the pressure controlled switch 34 mounted on the tank 33. It will also be noted that upon the elapse .of the programmed time for the lifting of oil from well 11, the associated switch in the timer 36, which according to the prior art may have a plurality of cam-operated switches, one for each of the lugs 73 on the multiple outlet valve 10, will be closed; and upon the closing of any one of the parallel connected switches in the timer 36 switch 1111 will be closed whereby a circuit is established through the contacts of normally closed, thermal delay switch 162 and through the valve motor 69, thus permitting valve motor 69 to start running, even though the microswitch 75 on the valve is at that instant held open by an index lug 73 on the valve, but upon running of the motor 69 to index the valve 10, microswitch 75 will promptly close to complete a circuit in parallel with the contacts of switch 102 which at that time is still closed because of the thermal delay; however, after a predetermined period of time the thermal time delay relay coil Oif switch 102 will open the contacts of that switch, but the relay coil of that switch 102 will continue to be excited until the timer 36 progresses sufficiently to close the parallel connected switch therein which it had just opened. Meantime, the valve motor 69 continues to run and index the multiple outlet valve until microswitch 75 is opened upon contact of its actuating finger 74 with the next index lug 73 which will open the microswitch 75 and break the circuit to the valve motor 69. At this time the rotor 47 in the multiple outlet valve 10 is aligned with the Teflon bushing 55 midway between the outlet port 41 and the outlet port 41a, assuming that the direction of rotation is clockwise, although it could be counterclockwise. In this position the bore through the Teflon bushing 55 is sealed off tightly against the inner periphery of the valve body 40, being urged thereagainst by the spring 59 and by the pressure of the operating gas against the end of the bushing 55 in the radial bore 51, so that the flow of operating gas under pressure is completely shut ofi by the multiple outlet valve.

When the programmed time elapses for the waiting period before lifting oil [from the next well, the timer 36 will close the parallel connected switch therein associated with that phase of the operation so as to again close switch 101 to complete a circuit through the contacts of normally closed thermal delay switch 102 and through the valve motor 69, thus permitting valve motor 69 to start running again and the indexing of the valve 10 proceeds as before until the microswitch 75 is opened upon contact of its actuating finger 74 with the next index lug 73 which will open the microswitch 75 and break the circuit to the valve motor 69 when the rotor 47 in the multiple outlet valve 10 is aligned with the Teflon bushing 55 overlying the outlet port 41a, as shown in FIG. 7, thereby resetting the mechanism to supply gas under pressure for the predetermined programmed length of time as determined by the setting of the cams in the timer 36, which after the programmed time will close the parallel connected microswitch therein associated with that phase of the operation to again initiate operation of the valve motor 69, as before, to index it to a position such that the Teflon bushing 55 is again sealed off against the inner wall of the valve body 40, this time midway between outlet ports 41a and 415. This cycle of operation continues throughout the 360-degree rotation of the multiple outlet valve, the valve body being provided with as many outlet ports as are necessary to accommodate the number of wells on the lease, it being understood that two index lugs 73 are provided for each such outlet port, one to align the rotor with the outlet port and the other to align the rotor with the wall median between adjacent ports, and it will also be understood that any or as many of the outlet ports may be closed oil as desired, and any scheduled stops may be eliminated by merely removing the corresponding lug, or lugs, 73, and of course the programming of the entire cycle of operations, and all phases thereof, are fully and independently adjustable for suitable programming to meet the demands and desires of the operator.

Referring now more particularly to FIGS. 813, connected to the two inch tubing 13 by a tubing collar 212 is an eccentrically swagged upper housing 213 onto the lower end of which there is threadedly connected the valve body 214. Threadedly connected to the lower end of the valve body is a lower housing 215 to which the bottom reservoir housing 216 is connected by tubing collar 217.

The valve body 214 is provided with two parallel through-bores comprising a valve receiving bore 218 and a tubing receiving bore 219. An intermittent valve 220, of well known prior art construction, is secured to the threaded upper end of the valve receiving bore 218 so as to extend upwardly into the upper housing 213, as shown in FIG. 9. Within the valve receiving bore 218 is a tubular piston guide 221 having a longitudinal through-bore within which the piston 222 is slidably positioned, the bore in the piston guide 221 being arranged to communicate with the intermittent valve 220 so as to receive operating gas therefrom under pressure for operation of the piston 222, as will be more fully described hereinafter. The piston guide 221 is provided in one side with a port 223 which is arranged in registry with a port 224 in the valve body 214 between the valve receiving bore 218 and the tubing receiving bore 219 so that intercornmunication is had between the tubing receiving bore and the through-bore in the piston guide 221, subject to control of the port 223 by the piston 222, as will be more fully described hereinafter. Depending downwardly from the piston 222 is a piston rod 225 which passes through a piston rod guide spacer 226 which abuts the lower end of the tubular piston guide and is provided with a plurality of tubular passages 227 for the passage of gas therethrough from the bore in the piston guide 221 and thence through the ball guide 228, the upper end of which abuts the piston rod guide spacer 226, the ball guide 228 being sealed in the valve receiving bore 218 by means of O ring 229. Interiorly, the ball guide 228 is arranged to form a cone shaped ball seat 230 which tapers downwardly and terminates in a substantially horizontal inturned ledge 231 having a sharp peripheral edge for engagement with the ball 232 which is loosely received Within the ball guide 228. A fluted push rod 233 projects through the cone shaped ball seat 230 for operative engagement with the ball 232, the push rod being urged upwardly against the ball by means of spring 234 which is received within a spring guide housing 235, the upper end of which abuts the lower end of the ball guide 228. A port 236 in the side wall of spring guide housing 235 is arranged in registry with a pont 237 in the outer wall of valve body 214 for the passage of gas under pressure outwardly from the valve receiving bore, as will be more fully described hereinafter. A plug 238 abuts the lower end of spring guide housing 235 and receives the bore end of spring 234. O ring 239 is provided about the plug 238 to seal it in place in the lower end of the valve receiving bore.

At the upward extension 240, the valve body 214 projects into the upper housing 213, and pressed over the upper end of extension 240 is a tubing guide sleeve 241 which extends upwardly in the upper housing 213 in axial alignment with the tubing receiving bore 219 and side by side with the intermittent valve 220. The tubing receiving bore 219 extends through the xtension 240 of the valve body 214 and interiorly the extension is provided at its upper end with a tapered wall 242 for receiving a tapered seating nipple 243 alfixed to the lower end of the tubing 14, the seating nippl 243 being guided into place in the extension of the valve body 214 by means of the tubing body valve sleeve 241 and 0 rings 244, 244, 244" being provided to seal the seating nipple in place in the valve body. Below the seating nipple 243, a lower aligned extension 245 of the tubing 14 continues downwardly through the tubing receiving bore in the valve body 214 and on down through the lower housing to near the end of the bottom reservoir housing 216, as shown in FIG. 8, the lower end 246 of the tubing 245 being crimped inwardly to leave an inlet 247 and yet retain within the tubing a rabbit 248.

As shown in FIGS. 13-16, the rabbit 248 comprises a plurality of steel balls 249 which are threaded on a small flexible cable 250 and separated by collars 251 which are threaded on the cable 250, one collar 251 being placed between adjacent balls 249. The end balls 249 in the string are recessed at 252 and the ends of the flexible cable 250 are soldered in place in these recesses so as to form a unitary but slightly flexible rabbit which is free to ride up and down in the one inch tubing.

The bottom reservoir housing 216 is provided at its lower end, as shown in FIG 8, with a standing valve comprising a ball 253 and valve seat 254, it being understood that the bottom reservoir housing 216 would usually extend from about 75 to about 150 feet below the valve body; and, as shown, according to my construction, the enlarged reservoir housing is much larger than the two inch tubing customarily used and thus provides a much larger and much more eflicient reservoir.

In the operation of my valve, operating gas under pressure of approximately 400 psi. is supplied through the tubing 13 and admitted through the intermittent valve 220 so as to drive the piston 222 downwardly to force the ball 232 onto its seat, as shown in FIG. 10 against the pressure of the spring 234. In this position, the piston 222 opens the port 223 so that the operating gas may pass from the intermittent valve through the ports 223, 224 and into the tubing receiving bore in the valve body and thence downwardly into the top of the oil accumulated in the reservoir defined by the reservoir housing 216, thus forcing the accumulated oil in the reservoir upwardly and outwardly through the one inch tubing 14. As is well known to those skilled in the art, the rabbit 248 serves to prevent gas from passing quickly out before the liquid starts to flow upwardly in the one-inch tubing, and when the flow stops th rabbit descends to the bottom of the tubing and rests upon the end 246.

As is well known, slugs of liquid will continue to be forced upwardly through the tubing 14 until the liquid accumulated in the reservoir has been discharged or unitl the pressure of the operating gas has been shut off at the top of the well as previously described.

When the pressure of the operating gas has been shut off at the top of the well, the piston 222 continues to hold the ball 232 on its seat until the pressure in the reservoir drops to approximately 60 p.s.i., then the spring 234 unseats the ball 232 and forces the piston 222 up into the position shown in FIG. 9 where the port 223 is then opened to communication below the piston 221 so that the gas entrapped in the reservoir can pass out through the ports 224, 223, thence downwardly through the tubular passages 227 past the fluted push rod 233 and thence outwardly through the ports 236, 137 and into the casing 12 where the pressure is only approximately 10 psi. Thus the back pressure on the reservoir is greatly relieved, and the oil from the well can flow more readily through the standing valve into the reservoir provided by the enlarged housing 216, according to my invention. It will be understood, of course, that as the level of the oil rises in the housing 216, it rises simultaneously in the one-inch tubing 245.

In order to have an efficient gas lift operation, all compressed gas has to be utilized and no waste can be tolerated. My valve has a snap closing action which is very important. It will be noted that piston 222 is very closely fitted in the tubular guide 221, and the unique construction of the cone-shaped leading wall of the seat of the ball valve 232 assures prompt and accurate seating of the ball in response to the immediate reaction of the piston 222 to the pressure of the gas on its upper face. The closing action of my valve is positively and substantially instantaneous, and the valve remains securely closed until the pressure drops below the spring tension. Only a single spring and few moving parts are used, thus making my valve simple in construction but extremely efficient in operation and long lasting. The tubing guide sleeve 241 is effective in seating the nipple 243 in the top of the valve housing, and the rings effectively seal the connection so that the operating gas under pressure cannot leak into the one inch tubing through which the oil is lifted except by passing around through the intermittent valve 220 in the manner heretofore described.

Having thus described my method and apparatus for automatic gas lift operation of oil wells, it will be apparent to those skilled in the art that the method and apparatus which I have provided is highly eflicient, entirely automatic, and economical in the use of gas in this closed system which provides for the recycling of the operating gas and the temporary storage of excess gas in one of the wells on the lease, but that many modifications and changes may be made without departing from the spirit or scope of my invention as defined by the appended claims.

I claim:

1, An automatic pressure relief valve comprising an eccentrically tubular upper housing, a valve body operatively connected to the lower end of said housing, a tubular reservoir housing, and means operatively connecting said reservoir housing to the lower end of said body, said valve body being provided with two parallel throughbores comprising a valve receiving bore and a tubing re ceiving bore, an intermittent valve in said upper housing, a tubular piston guide positioned in said valve receiving bore and provided in one side with a port and being also provided with a longitudinal through-bore communicating with said intermittent valve to receive operating gas therefrom under pressure, said valve body being provided with an intercommunicating port between said valve receiving bore and said tubing receiving bore and communicating with the port in said piston guide, a piston slidably mounted in said piston guide for controlling the flow of gas through said intercommunicating port, a piston rod depending from said piston, a ball guide sealed in said valve receiving bore and being provided interiorally with a downwardly tapering cone shaped ball seat having a substantially horizontal inturned ledge provided with a sharp peripheral seat, a ball arranged to seat on said seat, a fluted push rod mounted to slide through said ball seat, said valve body being provided with a relief port below said seat for the passage of gas under pressure outwardly from the valve receiving bore, spring means in said valve receiving bore operable at a predetermined pressure to urge said push rod against said ball to unseat it and push said ball against said piston rod to move said piston above said intercommunicating port for the passage of gas from said tubing receiving bore through said intercommunicating port and thence through said seat and outwardly through said relief port, means closing the lower end of said valve receiving bore, a tubing guide sleeve extending upwardly from said body into said upper housing in axial alignment with said tubing receiving bore, said body being provided with a tapered wall having 0 rings fixed therein for receiving a tapered seating nipple guided by said guide sleeve, tubing extending downwardly through said tubing receiving chamber into said reservoir housing and terminating at an inlet port therein, a check valve for said port including a rabbit comprising a plurality of balls interconnetced by a flexible cable, and spacer collar means on said cable between adjacent balls.

2. In an automatic pressure relief valve, a tubular upper housing, a valve body operatively connected to the lower end of said housing, a tubular reservoir housing, and means operatively connecting said reservoir housing to the lower end of said body, said valve body being provided with two parallel through-bores comprising a valve receiving bore and a tubing receiving bore, an intermittent valve in said upper housing, a tubular piston guide positioned in said valve receiving bore and provided in one side with a port and being also provided with a longitudinal through-bore communicating with said intermittent valve to receive operating gas therefrom under pressure, said valve body being provided with an intercommunicating port between said valve receiving bore and said tubing receiving bore and communicating with the port in said piston guide, a piston slidably mounted in said piston guide for controlling the flow of gas through said intercommunicating port, a piston rod depending from said piston, a ball guide in said valve receiving bore and being provided with a downwardly tapering cone shaped ball seat, a ball arranged to seat on said seat, a push rod mounted to slide through said ball seat, said valve body being provided with a relief port below said seat ,for the passage of gas under pressure outwardlyfrom the valve receiving bore, spring means in said valve receiving bore operable at a predetermined pressure'to urge said push rod against said ball to' insert it and push said ball against said piston rod to move said piston above said intercommunicating port for the passage of gas from said tubing receiving bore through said intercommunicating port and thence through said seat and outwardly through said relief port, means closing the lower end of said valve receiving bore, a tubing guide sleeve extending upwardly from said body into said upper housing in axial alignment with said tubing receiving bore, said body being provided with a tapered wall having rings fixed therein for receiving a tapered seating nipple guided by said guide sleeve, tubing extending downwardly through said tubing receiving chamber into said reservoir housing and terminating at an inlet port therein, and a check valve for said port including a rabbit.

3. In an automatic pressure relief valve, a tubular upper housing, a valve body operatively connected to the lower end of said housing, a tubular reservoir housing, and means operatively connecting said reservoir housing to the lower end of said body, said valve body being providedwith two parallel through-bores comprising a valve receiving bore and a tubing receiving bore, said valve body beingprovided with an intercommunicating port between said valve receiving bore and said tubing receiving bor e, a piston slidably mounted in said piston guide for controlling the flow of gas through said intercommunicating port, a piston rod depending from said piston, a ball guide sealed in said valve receiving bore and being provided interiorally with a downwardly tapering cone shaped ball seat having a substantially horizontal inturned ledge provided with a sharp peripheral seat, a ball arranged to seat on said seat, a push rod mounted to slide through said ball seat, said valve body also being provided with a relief port below said seat for the passage of gas under pressure outwardly from the valve receiving bore, and means in said valve receiving bore operable at a predetermined pressure to urge said push rod against said ball to unseat it and push said ball against said piston rod to move said piston above said intercommunicating port for the passage of gas from said tubingreceiving bore through said intercommunicating port and thence through said seat and outwardly through said relief port.

4. In a pneumaticldisplacement pump including an automatic pressure relief valve, the improvement comprising a valve body provided with two parallel throughbores constituting a valve receiving bore and a tubing receiving bore, a tubular piston guide positioned in said valve receiving bore and provided in one side with a port and being also provided with a longitudinal through-bore to receive operating gas under pressure, said valve body being provided with an intercommunicating port between said valve receiving bore and said tubing receiving bore and communicating with the port in said piston guide, a piston slidably mounted in said piston guide for controlling the flow of gas through said intercommunicating port, a piston rod depending from said piston, a ball guide a piston rod depending from said piston, a ball guide sealed in said valve receiving bore and being provided interiorally with a downwardly tapering cone shaped ball seat having a substantially horizontal inturned ledge .provided with a sharp peripheral seat, a ball arranged to seat on said seat, a fluted push rod mounted to slide through said ball seat, said valve body being provided with a relief port below said seat for the passage of gas under pressure outwardly from the valve receiving bore, spring means in said valve receiving bore operable at a predetermined pressure to urge said push rod against said rod to move said piston above said intercommunicating port for the passage of gas from said tubing receiving bore through said intercommunicating port and thence through said seat and outwardly through said relief port, means closing the lower end of said valve receiving bore, and a tubing guide sleeve extending upwardly from said body in axial alignment with said tubing receiving bore, said body being provided with a tapered wall having 0 rings fixed therein for receiving a tapered seating nipple guided by said guide sleeve.

5. In a pneumatic displacement pump including an automatic pressure relief valve, the improvement comprising a valve body provided with two parallel through-bores constituting a valve receiving bore and a tubing receiving bore, a tubular piston guide positioned in said valve reoeiving bore and provided in one side with a port and being also provided with a longitudinal through-bore to receive operating gas under pressure, said valve body being provided with an intercommunicating port between said valve receiving bore and said tubing receiving bore and communicating with the port in said piston guide, a piston slidably mounted in said piston guide for controlling the flow of gas through said intercommunicating port, a'piston rod depending from said piston, a ball guide in said valve receiving bore and being provided with a downwardly tapering cone shaped ball seat, a ball arranged to seat on said seat, a push rod mounted to slide through said ball seat, said valve body being provided with a relief port below said seat for the passage of gas under pressure outwardly from the valve receiving bore, spring means in said valve receiving bore operable at a predetermined pressure to urge said push rod against said ball to insert it and push said ball against said piston rod to move said piston above said intercommunicating port for the passage of gas from said tubing receiving bore through said intercommunicating port and thence through said seat and outwardly through said relief port, means closing the lower end of said valve receiving bore, and a tubing guide sleeve extending upwardly from said body in axial alignment with said tubing receiving bore, said body being provided with a tapered wall having 0 rings fixed therein for receiving a tapered seating nipple guided by said guide sleeve.

6. In a pneumatic displacement pump including an automatic pressure relief valve, the improvement comprising a valve body provided with two parallel through-bores constituting a valve receiving bore and a tubing receiving bore, said valve body being provided with an intercommunicating port between said valve receiving bore and said tubing receiving bore, a piston slidably mounted in said piston guide for controlling the flow of gas through said intercommunicating port, a piston rod depending from said piston, a ball guide sealed in said valve receiving bore and being provided interiorally with a downwardly tapering cone shaped ball seat having a substantially horizontal inturned ledge provided with a sharp peripheral seat, a ball arranged to seat on said seat, a push rod mounted to slide through said ball seat, said valve body also being provided with a relief port below said seat for the passage of gas under pressure outwardly from the valve receiving bore, and means in said valve receiving bore operable at a predetermined pressure to urge said push rod against said ball to unseat it and push said ball against said piston rod to move said piston above said intercommunicating port for the passage of gas from said tubing receiving bore through said intercommunicating port and thence through said seat and outwardly through said relief port.

7. An apparatus for automatic gas lift operation of a plurality of oil wells each having an outer casing, intermediate tubing within said casing and inner tubing within said intermediate tubing, and a pressure relief valve alternately interconnecting said intermediate tubing with said inner tubing and said inner tubing with said casing, a multiple outlet valve with an outlet connected respectively to the intermediate tubing in each of said wells for supplying operating gas under pressure thereto selectively, a gas and liquid separator connected to receive gas and liquid from the inner tubing in each of said wells, an oil and water separator connected to receive liquid from said gas and liquid separator and adapted to separate oil from water and separately discharge the same, an operating gas storage tank operatively connected to supply gas under pressure to said valve, pump means operably connected to supply and maintain gas under pressure in said storage tank within predetermined limits, and pipe means interconnecting said pump means with the gas outlet of said gas and liquid separator for supplying gas to said pump means, said multiple outlet valve being indexed in selectively supplying gas to said wells and including motive power means and timer means operatively connected to said valve for indexing said valve to supply operating gas under pressure to said wells according to a predetermined program.

8. Apparatus according to claim 7 including a pipe line interconnecting the casing of said one of said wells with the gas outlet of said gas and liquid separator and a bleedoff valve operatively connected to said pipe line.

9. In apparatus of the type for automatic gas lift operation of a plurality of oil wells, each of said wells having an outer casing, intermediate tubing within said casing, inner tubing within said intermediate tubing and a gas lift valve between said inner tubing and said intermediate tubing, an indexable multiple outlet valve with outlets communicating respectively with each of said gas lift valves in each of said wells for selectively supplying thereto operating gas under pressure, motive power means and timer means operatively connected to said valve for indexing said multiple outlet valve to supply operating gas under pressure to said wells according to a predetermined program, and each of said gas lift valves having means therein for equalizing the pressure between said outer casing and said intermediate tubing.

10. Apparatus according to claim 9 including a T-connection on said inner tubing in at least one of said wells for taking off fluid lifted through said inner tubing, one end of the cross bar on said T connected to said inner tubing, the other end of said cross 'bar connected to a tubular extension of said inner tubing for receiving a rabbit therein, means closing the other end of said extension, the leg of said T being connected to pipe leading from said well, and means interconnecting said pipe and said extension for permitting restricted flow of fluid from said extension to said pipe.

11. Apparatus according to claim 10 including means interconnecting said pipe with the casing of the associated well for the flow of gas from said casing to said pipe, and a check valve in said means permitting such flow and preventing flow in the opposite direction.

12. A method of pumping liquid from a plurality of wells each having an outer casing, intermediate tubing within said outer casing and inner tubing within said intermediate tubing, said method comprising periodically supplying operating gas under pressure from a common source to said intermediate tubing of each of said wells according to a prescribed program to lift fluid from said wells, separating gas and liquid from the fluid lifted from said wells, recycling a portion of said gas, temporarily storing another portion of said gas within the casing of one of said wells, and equalizing the pressures between said inner tubing and said intermediate tubing and the pressures between said inner tubing and said outer casing during each period.

13. Apparatus of the type for automatic gas lift pumping of a plurality of oil wells, each said well comprising a first tubing, an inner tubing within said first tubing and a pressure operated valve associated with said first tubing and said inner tubing, a multiple outlet valve means constructed and arranged to sequentially communicate with each of said first tubings for selectively supplying thereto operating gas under pressure whereby each of said pressure operated valves is periodically actuated, means at the ground surface for receiving fluid pumped from said wells, means for separating said pumping fluid into liquid and gas, and means for pressurizing said gas and recycling it through the tubings of said wells, said pressure operated valve of each well comprising means for periodically equalizing the pressure in said first tubing and said inner tubing.

References Cited by the Examiner UNITED STATES PATENTS 962,009 6/1910 Dinsmoor 166-52 2,034,798 3/1936 Clark 166-2 2,115,378 4/1938 Wolf 1662 2,362,442 11/1940 Baily 103232 2,620,740 9/1949 Garrett et a1 103-232 OTHER REFERENCES Uren: Petroleum Production Engineering, Oil Field Exploitation, 2nd edition, McGraw-Hill Book Co., Inc., N.Y., 1939.

JACOB L. NACKENOFF, Primary Examiner.

BENJAMIN HERSH, CHARLES E. OCONNELL,

Examiners. S. J. NOVOSAD, Assistant Examiner. 

3. IN AN AUTOMATIC PRESSURE RELIEF VALVE, TUBULAR UPPER HOUSING, A VALVE BODY OPERATIVELY CONNECTED TO THE LOWER END OF SAID HOUSING, A TUBULAR RESERVOIR HOUSING, AND MEANS OPERATIVELY CONNECTING SAID RESERVOIR HOUSING TO THE LOWER END OF SAID BODY, SAID VALVE BODY BEING PROVIDED WITH TWO PARALLEL THROUGH-BORES COMPRISING A VALVE RECEIVING BORE AND A TUBING RECEIVING BORE, SAID VALVE BODY BEING PROVIDED WITH AN INTERCOMMUNICATING PORT BETWEEN SAID VALVE RECEIVING BORE AND SAID TUBING RECEIVING BORE, A PISTON SLIDABLY MOUNTED IN SAID PISTON GUIDE FOR CONTROLLING THE FLOW OF GAS THROUGH SAID INTERCOMMUNICATING PORT, A PISTON ROD DEPENDING FROM SAID PISTON, BALL GUIDE SEALED IN SAID VALVE RECEIVING BORE AND BEING PROVIDED INTERIORALLY WITH A DOWNWARDLY TAPERING CONE SHAPED BALL SEAT HAVING A SUBSTANTIALLY HORIZONTAL INTURNED LEDGE PROVIDED WITH A SHARP PERIPHERAL SEAT, A BALL ARRANGED TO SEAT ON SID SEAT, A PUSH ROD MOUNTED TO SLIDE THROUGH SAID BALL SEAT, SAID VALVE BODY ALSO BEING PROVIDED WITH A RELIEF PORT BELOW SAID SEAT FOR THE PASSAGE OF GAS UNDER PRESSURE OUTWARDLY FROM THE VALVE RECEIVING BORE, AND MEANS IN SAID VALVE RECEIVING BORE OPERABLE AT A PREDETERMINED PRESSURE TO URGE SAID PUSH ROD AGAINST SAID BALL TO UNSEAT IT AND PUSH SAID BALL AGAINST SAID PISTON ROD TO MOVE SAID PISTON ABOVE SAID INTERCOMMUNICATING PORT FOR THE PASSAGE OF GAS FROM SAID TUBING RECEIVING BORE THROUGH SAID INTERCOMMUNICATING PORT AND THENCE THROUGH SAID SEAT AND OUTWARDLY THROUGH SAID RELIEF PORT. 9 IN APPARATUS OF THE TYPE FOR AUTOMATIC GAS LIFT OPERATION OF A PLURALITY OF OIL WELLS, EACH OF SAID WELLS HAVING AN OUTER CASING, INTERMEDIATE TUBING WITHIN SAID CASING, INNER TUBING WITHIN SAID INTERMEDIATE TUBING AND A GAS LIFT VALVE BETWEEN SAID INNER TUBING AND SAID INTERMEDIATE TUBING, AN INDEXABLE MULTIPLE OUTLET VALVE WITH OUTLETS COMMUNICATING RESPECTIVELY WITH EACH OF SAID GAS LIFT VALVES IN EACH OF SAID WELLS FOR SELECTIVELY SUPPLYING THERETO OPERATING GAS UNDER PRESSURE, MOTIVE POWER MEANS AND TIMER MEANS OPERATIVELY CONNECTED TO SAID VALVE FOR INDEXING SAID MULTIPLE OUTLET VALVE TO SUPPLY OPERATING GAS UNDER PRESSURE TO SAID WELLS ACCORDING TO A PREDETERMINED PROGRAM, AND EACH OF SAID GAS LIFT VALVES HAVING MEANS THEREIN FOR EQUALIZING THE PRESSURE BETWEEN SAID OUTER CASING AND SAID INTERMEDIATE TUBING.
 12. A METHOD OF PUMPING LIQUID FROM A PLURALITY OF WELLS EACH HAVING AN OUTER CASING, INTERMEDIATE TUBING WITHIN SAID OUTER CASING AND INNER TUBING WITHIN SID INTERMEDIATE TUBING, SAID METHOD COMPRISING PERIODICALLY SUPPLYING OPERATING GAS UNDER PRESSURE FROM A COMMON SOURCE TO SAID INTERMEDIATE TUBING OF EACH OF SAID WELLS ACCORDING TO A PRESCRIBED PROGRAM TO LIFT FLUID FROM SAID WELLS, SEPARATING GAS AND LIQUID FROM THE FLUID LIFTED FROM SAID WELLS, RECYCLING A PORTION OF SAID GAS, TEMPORARILY STORING ANOTHER PORTION OF SAID GAS WITHIN THE CASING OF ONE OF SAID WELLS, AND EQUALIZING THE PRESSURES BETWEEN SAID INNER TUBING AND SAID INTERMEDIATE TUBING AND THE PRESSURES BETWEEN SAID INNER TUBING AND SAID OUTER CASING DURING EACH PERIOD. 